Many utilities bury their pipes and cables (hereinafter, "conveyances") underground, both for cosmetic reasons, as well as to protect such conveyances from the elements. The utility undertaking burial records the location of the burial on a map to facilitate finding the conveyance at a later time. Contractors seeking to excavate in the vicinity of a conveyance will want to know the precise location of the conveyance to avoid damage thereto. While maps may provide a general indication of the location of the buried conveyance, most utilities invariably will dispatch a technician to physically locate the conveyance, typically using electromagnetic signaling for this purpose. Upon physically locating the conveyance, the technician will traditionally spray a water-soluble paint on the ground above the conveyance. Depending on weather and the extent of ground traffic, such marks may last two to three days. If excavation will occur for any longer duration, the technician must replenish the previously sprayed markings, often necessitating another visit to the job site.
In some instances, spray painting the markings may not suffice, requiring a more permanent method of indicating the location of the buried conveyance. To that end, utilities have resorted to placing metal flags at spaced intervals along the path of the buried conveyance. While the flags are more durable than the sprayed markings, the use of flags incurs disadvantages as well. Generally, the flags are simply pushed into the ground, allowing relatively easy removal and transfer to a different location. Unless the excavating contractor is specifically aware of the original location of the flags, the contractor may simply not notice any change in their location and presume it is safe to excavate in absence of the flags when in fact, buried conveyances exist. Moreover after deployment, the technician must remove the flags to avoid damage to lawn mowers and other similar equipment.
Thus, there is a need for a technique that provides a more permanent marking method to identify buried conveyances.